Smoke: keep one room clean
Shut the windows and run an air purifier sized for the room.
Wildfire smoke guide →Air quality in Oregon, county by county
21 Oregon counties have enough EPA monitor data to count bad-air days. Weighted by population, they averaged about 6 days a year from 2021 to 2025 when the air was unhealthy for sensitive groups or worse.
CDC's model, which estimates every county from monitors and satellites, gives the average Oregon county, weighted by population, about 9 smoky days (fine particles over 35.4 µg/m³, mostly wildfire smoke) and about 1 high-ozone day a year at its worst spot (2018 to 2022). See every county on the map.
Every Oregon county with monitors
Most bad-air days first. 10 have a full report. Compare with the worst and the cleanest counties in the US.
| County | Bad-air days a year | |
|---|---|---|
| Lane CountyEugeneSummer smoke | 19.4 | |
| Klamath CountyKlamath FallsSmokeozone not measured | 17.0 | |
| Josephine CountyGrants PassSmokeozone not measured | 16.2 | |
| Deschutes CountyBendSummer smoke | 14.8 | |
| Jackson CountyMedfordSummer smoke | 12.8 | |
| Harney CountySmokeozone not measured | 7.6 | |
| Lake CountySmokeozone not measured | 7.6 | |
| Crook CountyPrinevilleSmokeozone not measured | 6.6 | |
| Grant CountySmokeozone not measured | 6.4 | |
| Wallowa CountySmokeozone not measured | 3.8 | |
| Clackamas CountyOregon CityOzone and particles | 3.6 | |
| Umatilla CountyHermistonSummer smoke | 3.6 | |
| Marion CountySalemSummer smoke | 3.0 | |
| Jefferson CountySmokeozone not measured | 2.8 | |
| Union CountyLa GrandeSmokeozone not measured | 2.6 | |
| Baker CountyBaker CitySmokeozone not measured | 2.2 | |
| Wasco CountyThe DallesSmokeozone not measured | 1.8 | |
| Linn CountyAlbanySmokeozone not measured | 1.6 | |
| Multnomah CountyPortlandSummer smoke | 1.4 | |
| Washington CountyHillsboroSummer smoke | 1.4 | |
| Columbia CountySt. HelensSummer smoke | 1.0 | |
| No Oregon county with a monitor matches “”. Counties without a monitor aren't listed; a neighbor's numbers are a fair guide, or find it on the map. | ||
Counties without a monitor aren't listed. Air doesn't stop at the county line, so a neighbor's numbers are a fair guide.
What helps on a bad-air day
Check AirNow for today's reading and tomorrow's forecast, then match the step to the pollutant.
Upgrade the furnace filter
MERV 13 catches far more smoke than thin fiberglass filters.
Furnace filters →Questions people ask about air quality in Oregon
Which county in Oregon has the worst air?
Among Oregon counties with EPA monitors, Lane County had the most bad-air days from 2021 to 2025: about 19 bad-air days a year with an AQI over 100. That's about 1 day in 19.
How often is the air bad in Oregon?
Weighted by population, Oregon counties with monitors averaged about 6 bad-air days a year from 2021 to 2025 with an AQI over 100, when children, older adults and people with asthma should cut back outdoors. That's about 1 day in 60.
Which county in Oregon has the cleanest air?
Of the 21 counties with enough monitor data, Columbia County had the fewest: 1.0 a year from 2021 to 2025. Counties without monitors aren't ranked.
Where can I check today's air quality in Oregon?
AirNow, run by the EPA and its partners, shows current readings and forecasts by ZIP code, and its fire and smoke map adds smoke plumes and low-cost sensors.
Sources: EPA AirData county AQI summaries, 2021 to 2025; CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone, 2018 to 2022. Updated November 8, 2026.